I took delsym (dextromethorphan) to stop a persistent cough, now i feel like i need to cough but can't and end up almost throwing up. ?

Not unusual: The cough suppressant effect from Delsym, (dextromethorphan) although mild, is intended to reduce your cough. If you have sputum in the lung, suppressing the cough is not a good idea. The cough suppressant also make some people nauseous. If your cough has been present for more than a week or getting worse, you should see your doctor.